package com.ghc.api;

import org.apache.zookeeper.*;
import org.apache.zookeeper.data.Stat;

import java.io.IOException;

public class UpdateNoteData implements Watcher {

//    private static CountDownLatch countDownLatch = new CountDownLatch(1);

    private static ZooKeeper zooKeeper;

    /**
     * 建立会话
     */
    public static void main(String[] args) throws IOException, InterruptedException, KeeperException {

        /*
         客户端可以通过创建⼀个zk实例来连接zk服务器
         new Zookeeper(connectString,sesssionTimeOut,Wather)
         connectString: 连接地址：IP：端⼝
         sesssionTimeOut：会话超时时间：单位毫秒
         Wather：监听器(当特定事件触发监听时，zk会通过watcher通知到客户端)
         */
        zooKeeper = new ZooKeeper("127.0.0.1:2180", 5000, new UpdateNoteData());
        System.out.println(zooKeeper.getState());
        //计数工具类， CountDownLacth： 不让main结束， 让线程处于等待阻塞状态
//        countDownLatch.await();
        Thread.sleep(Integer.MAX_VALUE);
//        System.out.println("客户端与服务端回话真正建立了");
    }

    public void process(WatchedEvent watchedEvent) {
        //当连接创建了，服务端发送给客户端SyncConnected事件
        if(watchedEvent.getState() == Event.KeeperState.SyncConnected){
            //解除主程序CountDownLatch上的等待阻塞
            System.out.println("process方法执行了......");
//            countDownLatch.countDown();
            //创建节点 同步
            try {
                updayeNoteSync();
            } catch (KeeperException e) {
                e.printStackTrace();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    /*
     path:路径
     data:要修改的内容 byte[]
     version:为-1，表示对最新版本的数据进⾏修改
     zooKeeper.setData(path, data,version);
     */
    private void updayeNoteSync() throws KeeperException, InterruptedException {


        byte[] data = zooKeeper.getData("/ghc-persistent", false, null);
        System.out.println("修改前的值： " + new String(data));

        // 修改
        Stat stat = zooKeeper.setData("/ghc-persistent", "客户端修改了节点数据".getBytes(), -1);

        byte[] data2 = zooKeeper.getData("/ghc-persistent", false, null);
        System.out.println("修改后的值： " + new String(data2));
    }
}
